The Clinical Global Impression scale (CGI) is a classic instrument for making global assessments. This scale yields three different measures: 1. Severity of illness (assessment of patient's current symptom severity, referred to here as CGIs), 2. Global improvement (comparison of patient's baseline condition with his/her current condition, referred to here as CGIi), 3. Efficacy index (comparison of patient's baseline condition with a ratio of current therapeutic benefit to severity of side effects).